Exporting Shadow Properties with THREE.js Editor and GLTF

Your issue with persisting shadow properties in the THREE.js Editor and exporting them to GLTF is a common challenge. The THREE.js Editor doesn't automatically save changes made to userData during runtime scripts.

Understanding the Problem

When you modify userData in the start() function, these changes exist only during runtime and don't persist in the editor's state. This is because the editor maintains its own representation of the scene that gets reset when scripts finish executing.

Solutions

1. Use the Editor's API

Instead of modifying userData in the runtime script, you should use the editor's command system to make persistent changes:

JAVASCRIPTCopied
function start(event) {
  const editor = window.editor; // Access the editor instance
  
  this.traverse(child => {
    if (child.castShadow) {
      // Use the editor's command system to update userData
      editor.execute(new SetValueCommand(editor, child, 'userData', {
        ...child.userData,
        castShadow: true
      }));
      console.log(child);
    }
  });
}

2. Manual Approach

If you can't access the editor's API, you'll need to manually set the userData properties in the editor interface:

1. Select each object in the scene hierarchy
2. In the Properties panel, find the User Data field
3. Enter valid JSON like {"castShadow": true}
4. Apply these changes before exporting

3. Use GLTFExporter Options

When exporting, you can use the GLTFExporter's options to include shadow information:

JAVASCRIPTCopied
const exporter = new THREE.GLTFExporter();
exporter.parse(scene, function(gltf) {
  // Handle the exported GLTF
}, {
  // Include userData in the export
  binary: false,
  embedImages: true,
  includeCustomExtensions: true
});

4. Custom GLTF Extension

For a more robust solution, you might need to create a custom GLTF extension that specifically handles shadow properties. This is more advanced but ensures compatibility across different viewers.

Viewing userData in the Editor

Regarding your issue with viewing userData in the editor's text field, make sure you're entering valid JSON. The editor expects proper JSON format in the userData field. If it's showing as empty, it might be due to invalid JSON or the editor not refreshing the display after runtime changes.

Remember that for GLTF export purposes, you might need to use a specific structure in your userData that conforms to the GLTF extension you're targeting for shadow properties.

Exporting Shadow Properties with THREE.js Editor and GLTF

Your issue with persisting shadow properties in the THREE.js Editor and exporting them to GLTF is a common challenge. The THREE.js Editor doesn't automatically save changes made to objects during runtime scripts.

Understanding the Problem

When you modify userData in the start() function, these changes only exist during runtime and don't persist in the editor's state. The editor doesn't automatically capture runtime changes to objects.

Solutions

1. Use the Editor's API

Instead of trying to modify objects at runtime, you should use the editor's command system to make persistent changes:

JAVASCRIPTCopied
function start(event) {
  const editor = window.editor; // Access the editor instance
  
  this.traverse(child => {
    if (child.castShadow) {
      // Create a userData object if it doesn't exist
      const userData = child.userData || {};
      userData.castShadow = true;
      
      // Use the editor's command to set userData
      editor.execute(new SetValueCommand(editor, child, 'userData', userData));
    }
  });
}

2. Pre-configure Objects Before Export

Another approach is to manually set the userData properties through the editor interface before exporting:

1. Select each object in the scene hierarchy
2. In the properties panel, find the "User Data" field
3. Enter valid JSON like: {"castShadow": true, "receiveShadow": true}

3. Use GLTFExporter Options

When using the GLTFExporter programmatically (not in the editor), you can use its options to control how shadows are exported:

JAVASCRIPTCopied
const exporter = new GLTFExporter();
const options = {
  // Various options that might help with shadow properties
  // Check the GLTFExporter documentation for specifics
};
exporter.parse(scene, function(gltf) {
  // Handle the exported GLTF
}, options);

4. Post-Processing the GLTF

You could also export the GLTF and then use a script to post-process it, adding the shadow properties to the appropriate nodes in the exported JSON.

Viewing userData in the Editor

Regarding your issue with viewing userData in the editor's text field, make sure you're entering valid JSON in the field. The editor expects properly formatted JSON for the userData field. If it's showing as empty, it might be because:

1. The JSON is invalid
2. The editor is not properly displaying the data
3. The data is being reset elsewhere

Try manually entering a simple JSON object like {"test": true} and see if that persists.

Remember that for GLTF export specifically, you may need to use custom extensions or specific userData properties that the exporter recognizes for shadow properties.